Causes and Risk Factors
Primary causes are extrinsic: Prolonged pressure (e.g., >2 hours immobility), shear (sliding down in bed), friction (rubbing), and moisture (incontinence macerating skin). Intrinsic factors impair tolerance: Hypoxia, malnutrition, and inflammation exacerbate ischemia. In 2025 updates, COVID-19 sequelae highlight cytokine-driven vulnerability.
Risk factors per Braden Scale (scores ≤18 indicate risk): Immobility, limited activity, sensory impairment, moisture, nutrition deficits, friction/shear. Others: Age >70 (two-thirds of cases), diabetes, vascular disease, spinal cord injury, critical illness, obesity, or perioperative status. Up to 83% of hospitalized patients at risk may develop ulcers within 5 days.